In the first foreign-policy speech of his presidency, Joe Biden had a simple message for the world: “America is back.” But restoring the credibility of US diplomacy and implementing an effective foreign policy will be an uphill battle. To his credit, Biden is taking steps to reverse many of Donald Trump’s most damaging policies. As he noted in his speech, he already signed the paperwork to re-join the Paris climate agreement and has reengaged with the World Health Organization. Biden also announced the suspension of Trump’s planned troop withdrawals from Germany – a clear attempt to reassure America’s alienated European allies. Moreover, he warned Russian President Vladimir Putin that the days of the United States “rolling over in the face of Russia’s aggressive actions … are over.” And he pledged to end US support for the Saudi-led offensive in Yemen, and to step up diplomacy to end the catastrophic war. At the same time, Biden seems poised to uphold some of Trump’s more sensible policies. Notably, Trump was resolute in his desire to avoid “stupid, endless” wars in the Middle East, and he withdrew US troops from Syria, Iraq, and Afghanistan, resigning himself to the Afghan Taliban’s return to power. Biden is likely to take a similar approach (which, to be sure, began with Trump’s predecessor, Barack Obama). And for good reason: the US has expended vast amounts of blood and treasure in the Middle East, and has very little to show for it. As for the Israeli-Palestinian conflict, Biden has endorsed the Trump-brokered Abraham Accords between Israel and a number of Arab countries, even though they represented a strategic setback for the Palestinian cause. While he is not expected to endorse Trump’s bogus Israeli-Palestinian peace plan, he also seems unlikely to invest much political capital in advancing the two-state solution – by now a lost cause. But there remain major foreign-policy tests ahead. Start with Iran, which Biden barely mentioned in his recent speech. During his campaign, Biden promised to return to the 2015 Iran nuclear deal, the so-called Joint Comprehensive Plan of Action, which Obama negotiated and Trump abandoned. To this end, the Biden administration will have to persuade Iran to stop enriching uranium beyond JCPOA-imposed limits and agree to new negotiations, before the US lifts its punishing economic sanctions on the country. Of course, Iran wants sanctions relief first, but compromise is entirely achievable. The bigger challenge will be overcoming resistance from America’s regional allies, especially Israel, whose military is already preparing for possible offensive action against Iran. The strategic viability of such an offensive is far from clear. In 2012, Israel’s then-minister of defense, Ehud Barak, concluded that Iran’s nuclear program was already nearing the “immunity zone,” where an attack could not derail it, owing to the country’s accumulated “know-how, raw materials, experience, and equipment.” Nonetheless, Israeli Prime Minister Binyamin Netanyahu has a proven record as a spoiler, and the Biden administration must be careful not to allow him to reprise that role. Despite being crippled by sanctions, Iran retains considerable bargaining power. It enjoys the support of Russia and China, and Biden seems to recognize that the US cannot afford to wage another war in the Middle East. While Biden gave short shrift to Iran in his speech, he did not mention North Korea at all. Here, the dilemma is no longer how to reverse nuclearization, but rather how to mitigate any threat to America’s allies and the US mainland. With diplomacy having consistently failed, and military action sure to be an unmitigated calamity, the Biden administration has few good options. Finally, there is the China challenge. In his speech, Biden pledged to “confront” China’s economic abuses, “counter its aggressive, coercive action,” and “push back” against its “attack” on human rights, intellectual property, and global governance. But he also promised to work with China “when it’s in America’s interest to do so.” Walking this line will not be easy. An excessively restrained approach would allow China to encroach further on the territory of US allies in Asia, erode America’s leadership in high-tech industries, and challenge the US dollar’s primacy. But an overly tough approach would rule out much-needed cooperation on shared challenges like climate change, and increase the risk of a potentially catastrophic military confrontation. For the US, the key to balancing these risks is to focus on managing strategic competition, not asserting dominance. The days of US hegemony are over, and America’s dysfunctional political system is incapable of countering China’s development strategy even by upgrading its own obsolete infrastructure. The only way to rein in an increasingly assertive China is through cooperation with empowered allies. Fortunately, Biden is aware of US deficiencies and has pledged to build a global alliance of democracies for precisely the purpose of competing with China. But goal-setting is just the first step. If the US is to work effectively with allies, let alone competitors, it needs credibility. And that is in short supply nowadays. A country’s international credibility and, thus, the effectiveness of its foreign policy must be built on strong domestic foundations. But, from its botched pandemic response to the storming of the US Capitol on January 6, America’s political dysfunction has lately been on stark display. The “City on a Hill” has lost its shine. US foreign policy suffers from endemic inconsistency. Even if Biden manages to reach agreements with allies and competitors, who is to say that his successor will not simply abandon them, as Trump did during his term? With the US Senate having voted to acquit him of inciting the mob on January 6, Trump himself may run again in 2024. And he could well win, not least because he may not be facing an incumbent. (At 78, Biden is already the oldest president in US history.) So, yes, America is set to rejoin the rest of the world. But whether the power of its example will convince skeptical partners, as Biden hopes, remains to be seen.